git.r.bdr.sh - rbdr/mobius/blob - hotline/file_header.go

   1 package hotline
   2
   3 import (
   4         "encoding/binary"
   5         "io"
   6         "slices"
   7 )
   8
   9 type FileHeader struct {
  10         Size     [2]byte // Total size of FileHeader payload
  11         Type     [2]byte // 0 for file, 1 for dir
  12         FilePath []byte  // encoded file path
  13
  14         readOffset int // Internal offset to track read progress
  15 }
  16
  17 func NewFileHeader(fileName string, isDir bool) FileHeader {
  18         fh := FileHeader{
  19                 Type:     [2]byte{0x00, 0x00},
  20                 FilePath: EncodeFilePath(fileName),
  21         }
  22         if isDir {
  23                 fh.Type = [2]byte{0x00, 0x01}
  24         }
  25
  26         encodedPathLen := uint16(len(fh.FilePath) + len(fh.Type))
  27         binary.BigEndian.PutUint16(fh.Size[:], encodedPathLen)
  28
  29         return fh
  30 }
  31
  32 func (fh *FileHeader) Read(p []byte) (int, error) {
  33         buf := slices.Concat(
  34                 fh.Size[:],
  35                 fh.Type[:],
  36                 fh.FilePath,
  37         )
  38
  39         if fh.readOffset >= len(buf) {
  40                 return 0, io.EOF // All bytes have been read
  41         }
  42
  43         n := copy(p, buf[fh.readOffset:])
  44         fh.readOffset += n
  45
  46         return n, nil
  47 }